Analysis of machine tool bed casting measure hardness increase

Raise the machine bed casting casting machine measures the hardness of the material which is characterized by: the machine base castings large size, up to several meters long; mass up to 10t or more, wall thickness 15 ~ 30mm. Its requirements are: a good precision stability and shock absorption, high elastic modulus, suitable compressive strength, excellent hardness and excellent abrasion resistance; in the process requires good casting properties, with higher resistance to deformation, and easy machining, and requires lower production costs, such as available cupola melting, using a relatively small amount of alloying elements and the like. To meet these requirements, it should pearlite microstructure, with a length of less than 250tim and uniform distribution of A-type graphite, also requires a certain amount of phosphorus binary eutectic. China's machine tool commonly used HT250 and HT300 cast iron castings as breeding material.